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UPDATED: NHBB explosion in Peterborough likely took place in acid room

The explosion at New Hampshire Ball Bearings Monday afternoon likely originated from an "acid room" where different chemicals are used, Deputy State Fire Marshall Max Schultz said at a press conference outside the manufacturing plant on Route 202 Tuesday just before noon.

UPDATE: In a letter to employees on the website of New Hampshire Ball Bearings Wednesday afternoon, NHBB president Gary Yomantas indicated the company commits to paying the base wages to every employee prevented from working due to the plant shutdown or limited operation.

All work shifts were canceled at the plant Wednesday, and select departments plan to resume operations on Thursday. Those departments include component fabrication, component fabrication support groups, and office personnel.

UPDATE: A release from state fire marshal J.William Degnan and Peterborough Fire Chief Joseph P. Lenox III Wednesday afternoon indicated that the investigation into Monday's explosion at New Hampshire Ball Bearings is continuing.

The release indicated the incident is being classified as an industrial accident and the cause of the explosion has been determined to be directly related to a nitric acid reaction. Nitric acid is an oxidizing agent and is commonly used in industrial processes.

Late Tuesday evening the on-scene portion of the investigation was completed, and the facility was turned back over to NHBB management so they could begin remediation and clean-up. Clean Harbors Environmental Services will be assisting NHBB with this effort over the next several days.

A final report regarding the exact origin and cause and any recommendations as a result of the investigation will also be several weeks away.

Previous story follows:

PETERBOROUGH — The explosion at New Hampshire Ball Bearings appears to have originated from a drum in the "acid room" where different chemicals are used, Deputy State Fire Marshall Max Schultz said at a news conference outside the manufacturing plant on Route 202 Tuesday.

"This occurred shortly after a shift change, so we're trying to look at the shift change, what that process was, who was involved and what happened," Schultz said. "It takes time. There are a lot of people to talk to and a lot of information to gather."

The investigation includes local, state and federal agencies, he said.

Two critically injured employees have not been interviewed yet, he said. The 14 people who were hurt Monday afternoon suffered burns and trauma injuries, officials said.

The blast did substantial damage to the interior of the building, Schultz said, but no one was "right in the proximity of the drum in the acid room."

Investigators are also trying to determine if one or two explosions occurred, since some employees reported hearing a small pop just before the large blast that shook the building Monday at 3:37 p.m., he said.

"We're treating this as an industrial incident that occurred," Schultz said. "We don't believe there is any criminal aspect at this time."

The company announced on its website Tuesday night that all work shifts have been canceled for today, "with the goal of resuming operations on Thursday in select departments, including component fabrication, component fabrication support groups, and office personnel."

The site also announced that counseling for employees will be available today at the satellite training facility at 375 Jaffrey Road, 11 a.m. to 5 p.m.

Earlier Tuesday, Rich Bardellini, NHBB vice president of manufacturing, said employees would not be returning to work until a hazardous materials team and structural engineers officially say the building is safe.

"Our goal is to restore operations in those areas not impacted as quickly as possible," he said. "However, we will not have our employees return until state officials and NHBB management are convinced beyond any doubt that it is safe to return to work."

Bardellini would not go into details about what chemicals are used in the acid room other than to say, "Basically what we do in that room is the surface treatment of our parts."

Fourteen people — including 10 employees and four private contractors — were taken to Monadnock Community Hospital Monday after the blast, Peterborough Fire Chief Joe Lenox said.

All but two were treated and released, he said. Lenox said he did not have an update on the conditions of the critically injured workers; one is at UMass Medical Center and the other at Massachusetts General.

Lenox said the Peterborough Fire Department does yearly evacuation drills at NHBB.

"They do quarterly evacuation drills at this plant, and it really paid off," Lenox said. "That's probably the reason why we only have 14 injuries."

Ted Lawrence, a technical specialist in the grinding department on the second floor, described the evacuation as "very quick, and a little panicked, but very quick."

Tuesday afternoon, Lawrence met up with co-workers at a bar in Peterborough. He and his co-workers are concerned about being out of work as well as the condition of the building, he said.

"We don't know the structure of the building, if it is safe and sound," he said.

Second-floor assembly worker Cheryl Christian of Dublin said she has been with the company for many years, so she is not concerned about a few days at home.

"I've got enough vacation time. I could use that if I had to, but some people don't have that flexibility," Christian said.

Though, she hasn't heard, she expects NHBB would pay employees for Tuesday at least. NHBB is good to its employees and offers good benefits, she said.

Bardellini said NHBB officials are "grateful beyond words" for the response from local and state emergency teams on Monday. He called the response "overwhelming, immediate, complete." The company's local and larger community also responded, he said.

"Within hours, we heard from our neighbors, our community, our local government officials, our parent company, our customers, and many others, to assist us in any way they can. We ask that all of you keep our employees, their families and other impacted in your thoughts and prayers. Our first and primary concern is for them,' Bardellini said.

"It seems like the damage is relatively isolated to a relatively small part of the plant," she told reporters when she returned to the State House on Tuesday. She said state economic development officials are ready to help find additional space for plant operations to resume if that is needed.

A section of Route 4 was shut down Wednesday afternoon after a three-vehicle accident occurred, killing one motorist, according to police officials.

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